Vitamin D levels lacking in millions of U.S. children

Millions of American children may not be getting enough vitamin D, according to a new report out today. The sunshine vitamin is essential for helping kids build healthy bones and ward off rickets. Plus, new evidence shows it may ward off colds, childhood wheezing, and winter-related eczema. The study, published in the November issue of Pediatrics, is the most up-to-date look at vitamin D levels in U.S. children. The research adds brawn to the existing evidence that vitamin D levels are dangerously low, especially in black and Hispanic children. “If our associations are correct, this is a big problem,” says Jonathan Mansback, MD, a pediatrician at Children’s Hospital Boston, and the study’s lead author.

Using data from the National Health and Nutrition Examination Survey (NHANES), the scientists examined blood levels of vitamin D in 5,000 children (ages 1 to 11) representative of the country’s population. They found that roughly 20 percent those tested fell below optimal levels. Humans get vitamin D primarily through sunshine. But low levels of sunlight in northern latitudes from November through March, coupled with the increased number of parents who slather their children with sunscreen, means kids’ vitamin D levels are getting the double whammy. (Note: sunscreen use in childhood does help stave off future melanoma, so don’t ditch the stuff.)

Even more vexing to researchers (and, no doubt, to parents) is that experts are divided on exactly how to define an “optimal level” of vitamin D. Currently, the American Academy of Pediatrics recommends children have vitamin D blood levels of at least 50 nmol/L (nanomoles per liter). To reach that goal, children must get 400 international units (IU) of vitamin D a day. But pediatricians, such as Mansback, worry that 400 IU is too low. Until they figure it out, study authors suggest parents consider giving their kids supplemental vitamin D since it’s difficult to get enough from food. Start with a good, children’s multi-vitamin, which should include 400 IU of vitamin D, says Mansback. But, if you live in a place with cold, dark winters (Vermont vs. Southern California), you might also want to go the extra mile, he says, and give children vitamin D drops. (Of course, talk to your pediatrician first.) “Because the safety profile of vitamin D is so high,” he says, “getting a little too much is better than coming up short.”